The Lenten journey of conversion requires Christians to rediscover the "deepest truth" about themselves, cast off their masks and take on the courage to live truth, a prominent Carmelite priest told the pope and Vatican officials.

In the first days of Lenten spiritual exercises for the Roman Curia, the church's central administration, Carmelite Fr. Bruno Secondin drew from the life of the prophet Elijah to invite Vatican officials to reflect on whether their hearts "really belong to the Lord" or whether they rely on external gestures.

The head of the Ukrainian Catholic Church invited Pope Francis to visit the war-torn nation, saying it would help bring peace.

"It would be a prophetic gesture that would show the power of prayer and Christian solidarity, give us courage and hope and build a better future for everyone," said Archbishop Sviatoslav Shevchuk, major archbishop of Kiev-Halych.

Real fasting isn't just restricting food choices. It must also include cleansing the heart of all selfishness and making room in one's life for those in need and those who have sinned and need healing, Pope Francis said.

Faith without concrete acts of charity is not only hypocritical, "it is dead. What good is it?" he asked, criticizing those who hide behind a veil of piety while unjustly treating others, such as denying workers fair wages, a pension and health care.

Liberty and equality are not enough for the well-being of a nation; there must also be a strong sense of brotherhood that is first developed and nurtured in the family, Pope Francis said.

Without seeing each other as brothers and sisters, a nation's citizens may distort these values, letting freedom and equality "be filled with individualism and conformity," he said at his general audience Wednesday.

Every human heart has the capacity to do good or evil and to build or to destroy, but the strength to make the right choice comes from Christ, Pope Francis said.

"But why are we like this? Because we have this possibility for destruction, this is the problem," he said Tuesday during his homily in a morning Mass offered for the 21 Egyptian Coptic Christians who were beheaded by Islamic State militants in Libya.